This research will make detailed investigations of the human electroretinogram and the visually evoked cortical potential using stimulus alternation. An advantage of alternation is that it produces results that are uncomplicated by stray light. Quantitative studies are to be made of recordings that are produced by stimulation of peripheral regions of the retina. The recording conditions and subsequent analyses will permit a comparison of the results with data from psychophysics and other areas of visual science. In this year's experiments, alternating stimuli will be used to evaluate the visual acuity of the retinal periphery using electrophysiological techniques. Experiments will be conducted to isolate "on and off effects" components in the electroretinogram and the evoked potentials. Response will be resolved into their components using statistical procedures, and the components will be related to sensory functions. In a final set of experiments, an analysis will be made of potentials that accompany blinks as well as those that accompany saccadic eye movements. Attention will be given to the role that these motor activities play in maintaining vision.